U.S. patent application number 11/672434 was filed with the patent office on 2007-10-04 for systems for treating bone.
Invention is credited to John H. Shadduck.
Application Number | 20070233250 11/672434 |
Document ID | / |
Family ID | 38560347 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070233250 |
Kind Code |
A1 |
Shadduck; John H. |
October 4, 2007 |
SYSTEMS FOR TREATING BONE
Abstract
The present invention relates in certain embodiments to medical
devices for treating vertebral compression fractures. In one
embodiment, the invention relate to systems for introducing fill
material into a vertebral body that slowly expands vertebral height
without explosive balloon expansion as in kyphoplasty. The system
provides a fill material that infills a vertebra without flowable
bone cement as used in kyphoplasty and vertebropalsty procedures.
Thus, the bone fill system prevents the possibility of
extravasation of material into the spinal canal which occurs in a
significant number of kyphoplasty and vertebropalsty procedures. An
energy source can apply energy to a substantially rigid implant
material in order to soften, melt, or fracture the implant material
to infill a vertebral body.
Inventors: |
Shadduck; John H.; (Tiburon,
CA) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
38560347 |
Appl. No.: |
11/672434 |
Filed: |
February 7, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60765852 |
Feb 7, 2006 |
|
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Current U.S.
Class: |
623/17.11 |
Current CPC
Class: |
A61B 18/02 20130101;
A61B 18/08 20130101; A61B 2017/564 20130101; A61B 18/1206 20130101;
A61B 17/7095 20130101 |
Class at
Publication: |
623/017.11 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. A system for treating a bone, comprising: an elongated
introducer configured for insertion in a bone, the introducer
defining a passage extending therethrough along an axis of the
introducer; an elongated implant body configured for insertion
through the passage into the bone, the elongated implant body
having a substantially unyielding configuration; and an energy
source coupled to the elongated introducer, the energy source
configured to transform at least a portion of the elongated implant
into a yielding configuration to infill the bone.
2. The system of claim 1, wherein the energy source is at least one
of an Rf energy source, a resistive heat source, a light energy
source, a microwave energy source, an ultrasound energy source, a
magnetic energy source, a mechanical energy source and a cryogenic
source.
3. The system of claim 2, wherein the energy source is configured
to cause at least one of softening, melting, cutting, sacrificing
and fracturing said at least one portion of the implant body.
4. The system of claim 1, wherein the energy source comprises at
least one energy emitter disposed proximate a distal end of the
introducer, the at least one emitter configured to direct thermal
energy to at least a portion of the elongated implant.
5. The system of claim 2, wherein the mechanical source comprises
an implant drive mechanism and an opening formed on a side of the
elongated introducer, said opening configured to fracture at least
a portion of the elongated implant as the implant is advanced
through the introducer.
6. The system of claim 2, wherein the mechanical source comprises
an implant drive mechanism and at least one cutting element coupled
to the introducer, said at least one cutting element configured to
cut at least a portion of the elongated implant as the implant is
advanced through the introducer.
7. The system of claim 1, wherein the energy source is a cryogenic
source configured to be coupled to the introducer, the cryogenic
source configured to fragment at least a portion of the elongated
implant as the implant is advanced through the introducer.
8. The system of claim 1, further comprising a controller in
communication with the energy source, the controller configured to
control the application of energy by the energy source to at least
a portion of the elongated implant.
9. The system of claim 1, wherein the elongated implant body has a
helical configuration, the implant body configured to be helically
driven through the introducer.
10. The system of claim 9, wherein the elongated implant body
comprises a plurality of implant elements, wherein adjacent implant
elements are coupled to each other via keys on said adjacent
elements.
11. The system of claim 1, wherein the elongated implant body
comprises a plurality of helically intertwined portions.
12. The system of claim 1, wherein the elongated implant body
comprises a plurality of implant elements, wherein adjacent implant
elements are coupled with each other via a sacrificial portion,
said energy source configured to effect at least one of fracturing,
melting, dissolving and fragmenting of said sacrificial
portion.
13. The system of claim 1, wherein the elongated implant body
defines a passage therethrough configured to allow a flow of bone
fill material therethrough for introduction into the bone.
14. A system for treating a vertebra, comprising: an elongated
introducer configured for insertion in a vertebral body, the
introducer defining a passage extending therethrough along an axis
of the introducer; a substantially rigid implant configured for
insertion through the passage into the vertebral body, the implant
comprising a plurality of implant elements coupled with each other
via a junction, the junction transformable between a substantially
unyielding configuration to a substantially yielding configuration;
and an energy source coupled to the elongated introducer, the
energy source configured to separate at least one implant element
from the implant at said junction, the separated implant element
advanced into the vertebral body to infill the vertebral body.
15. The system of claim 14, wherein the energy source is at least
one of an Rf energy source, a resistive heat source, a light energy
source, a microwave energy source, an ultrasound energy source, a
magnetic energy source, a mechanical energy source and a cryogenic
source.
16. The system of claim 15, wherein the energy source is configured
to direct thermal energy to at least said junction to melt said
junction to separate the implant element from the substantially
rigid implant.
17. The system of claim 14, wherein the energy source is a
mechanical source comprising an implant drive mechanism and a
member configured to effect at least one of cutting, fracturing and
sacrificing of said junction to separate said implant element from
the substantially rigid implant.
18. The system of claim 14, wherein the substantially rigid implant
has a helical configuration.
19. The system of claim 14, wherein the substantially rigid implant
defines a passage therethrough along an axis of the substantially
rigid implant, said passage dimensioned to allow a flow of bone
fill material therethrough for insertion into the vertebral
body.
20. A system for the infill of the interior of a bone, comprising:
an elongated introducer configured for introduction into a bone,
the introducer defining a passage extending therethrough along an
axis of the introducer; a plurality of implants dimensioned for
advancement along the introducer, each adjacent pair of the
plurality of implants coupled to each other via a junction, each
implant having a first helical feature for cooperating with a
second helical feature on the introducer to helically advance the
implants through the passage and into the bone.
21. The system of claim 20, wherein the implants are keyed with one
another.
22. The system of claim 20, wherein the implants are coupled to one
another via a sacrificial portion.
23. The system of claim 22 further comprising an energy source
configured to detach at least one of the plurality of implants
proximate said sacrificial portion.
24. A system for treating a bone, comprising: an elongated
introducer configured for insertion into a bone, the introducer
defining a passage extending therethrough along an axis of the
introducer; an elongated implant body configured for insertion into
the bone along said introducer, the elongated implant body having a
substantially unyielding configuration, a surface of the implant
body configured to engage with a surface of the introducer for
advancement of the implant body along the introducer; and means for
transforming at least a portion of the elongated implant from a
substantially unyielding configuration to a yielding configuration
to infill the bone.
25. An implant configured for insertion into a bone, comprising: an
elongated body sized for introduction along an introducer into a
bone, at least a portion of the elongated body being transformable
from a substantially unyielding configuration to a yielding
configuration configured for infilling the bone.
26. The implant of claim 25, wherein the elongated body comprises
at least one of a polymeric material, a ceramic material, a glass
material or a combination thereof.
27. The implant of claim 26, wherein the material is
biocompatible.
28. The implant of claim 26, wherein the material comprises
PMMA.
29. The implant of claim 25, wherein the elongated body defines a
passage therethrough along an axis thereof, the passage configured
for insertion of bone cement therethrough into the bone.
30. The implant of claim 25, wherein the elongated body has a
helical feature configured to engage a corresponding feature on the
introducer.
31. The implant of claim 30, wherein the helical feature is formed
on an outer surface of the elongated body.
32. The implant of claim 30, wherein the helical feature is formed
on an inner surface of the elongated body.
33. The implant of claim 25, wherein the elongated body comprises a
plurality of implant elements and adjacent implant elements are
coupled to each other via a junction.
34. The implant of claim 33, wherein the junction is a sacrificial
junction.
35. The implant of claim 33, wherein at least one element is
severable from an adjacent element proximate said junction via the
application of at least one of thermal energy, mechanical energy
and cryogenic cooling.
36. The implant of claim 35, wherein thermal energy is applied by
at least one of an Rf source, a resistive heat source, a light
energy source, a microwave source, an ultrasound source, a magnetic
source and a cryogenic source.
37. The implant of claim 33, wherein the junction comprises
interlocking key features formed on adjacent implant elements.
38. An implant configured for insertion into a bone, comprising: an
elongated body having at least one helical feature and sized for
introduction into a bone, at least a portion of the elongated body
being severable from the elongated portion for infilling the
bone.
39. The implant of claim 38, wherein the elongated body comprises a
plurality of implant elements, adjacent implant elements coupled to
each other via a junction.
40. The implant of claim 39, wherein the junction comprises
interlocking key features formed on adjacent implant elements.
41. The implant of claim 39, wherein the junction comprises a
sacrificial portion.
42. The implant of claim 38, wherein the elongated body defines a
passage therethrough along an axis thereof, the passage configured
for insertion of bone cement therethrough into the bone.
43. The implant of claim 38, wherein the at least one helical
feature is formed on an outer surface of the elongated body, the
helical feature configured for engagement with a corresponding
feature on an introducer through which the elongated body is
advanced into the bone.
44. The implant of claim 38, wherein the at least one helical
feature is formed on an inner surface of the elongated body, the
helical feature configured for engagement with a corresponding
feature on a shaft along which the elongated body is advanced into
the bone.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit under 35 U.S.C. .sctn.
119(e) of U.S. Provisional Patent Application No. 60/765,852, filed
on Feb. 7, 2006. This application is also related to U.S. patent
application Ser. No. 11/165,652, filed Jun. 24, 2005, now U.S. Pub.
No. 2006-0122623; U.S. patent application Ser. No. 11/165,651,
filed Jun. 24, 2005, now U.S. Pub. No. 2006-0122622; U.S. patent
application Ser. No. 11/208,448, filed Aug. 20, 2005, now U.S. Pub.
No. 2006-0122621; U.S. patent application Ser. No. 11/469,764,
filed Sep. 1, 2006; U.S. application Ser. No. 11/209,035, filed
Aug. 22, 2005, now U.S. Pub. No. 2006-0122625; U.S. application
Ser. No. 11/196,045, filed Aug. 2, 2005, now U.S. Pub. No.
2006-0122624; and U.S. application Ser. No. ___/______, filed Feb.
7, 2007 (Atty. Docket No. DFINE.031A) and titled "METHODS FOR
TREATING BONE." The entire contents of all of the above
applications are hereby incorporated by reference and should be
considered a part of this specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates in certain embodiments to
medical devices for osteoplasty procedures such as treating
vertebral compression fractures. More particularly, embodiments of
the invention relate to instruments and systems for introducing
fill material into a vertebral body that (i) slowly expands
vertebral height without explosive balloon expansion as in
kyphoplasty, and (ii) that infills a vertebra without flowable
material as in kyphoplasty and vertebropalsty wherein bone cement
can result in extravasation into the spinal canal.
[0004] 2. Description of the Related Art
[0005] Osteoporotic fractures are prevalent in the elderly, with an
annual estimate of 1.5 million fractures in the United States
alone. These include 750,000 vertebral compression fractures (VCFs)
and 250,000 hip fractures. The annual cost of osteoporotic
fractures in the United States has been estimated at $13.8 billion.
The prevalence of VCFs in women age 50 and older has been estimated
at 26%. The prevalence increases with age, reaching 40% among
80-year-old women. Medical advances aimed at slowing or arresting
bone loss from aging have not provided solutions to this problem.
Further, the population affected will grow steadily as life
expectancy increases. Osteoporosis affects the entire skeleton but
most commonly causes fractures in the spine and hip. Spinal or
vertebral fractures also cause other serious side effects, with
patients suffering from loss of height, deformity and persistent
pain which can significantly impair mobility and quality of life.
Fracture pain usually lasts 4 to 6 weeks, with intense pain at the
fracture site. Chronic pain often occurs when one vertebral level
is greatly collapsed or multiple levels are collapsed.
[0006] Postmenopausal women are predisposed to fractures, such as
in the vertebrae, due to a decrease in bone mineral density that
accompanies postmenopausal osteoporosis. Osteoporosis is a
pathologic state that literally means "porous bones". Skeletal
bones are made up of a thick cortical shell and a strong inner
meshwork, or cancellous bone, of with collagen, calcium salts and
other minerals. Cancellous bone is similar to a honeycomb, with
blood vessels and bone marrow in the spaces. Osteoporosis describes
a condition of decreased bone mass that leads to fragile bones
which are at an increased risk for fractures. In an osteoporosis
bone, the sponge-like cancellous bone has pores or voids that
increase in dimension making the bone very fragile. In young,
healthy bone tissue, bone breakdown occurs continually as the
result of osteoclast activity, but the breakdown is balanced by new
bone formation by osteoblasts. In an elderly patient, bone
resorption can surpass bone formation thus resulting in
deterioration of bone density. Osteoporosis occurs largely without
symptoms until a fracture occurs.
[0007] Vertebroplasty and kyphoplasty are recently developed
techniques for treating vertebral compression fractures.
Percutaneous vertebroplasty was first reported by a French group in
1987 for the treatment of painful hemangiomas. In the 1990's,
percutaneous vertebroplasty was extended to indications including
osteoporotic vertebral compression fractures, traumatic compression
fractures, and painful vertebral metastasis. Vertebroplasty is the
percutaneous injection of PMMA (polymethylmethacrylate) into a
fractured vertebral body via a trocar and cannula. The targeted
vertebrae are identified under fluoroscopy. A needle is introduced
into the vertebrae body under fluoroscopic control, to allow direct
visualization. A bilateral transpedicular (through the pedicle of
the vertebrae) approach is typical but the procedure can be done
unilaterally. The bilateral transpedicular approach allows for more
uniform PMMA infill of the vertebra.
[0008] In a bilateral approach, approximately 1 to 4 ml of PMMA is
used on each side of the vertebra. Since the PMMA needs to be is
forced into the cancellous bone, the techniques require high
pressures and fairly low viscosity cement. Since the cortical bone
of the targeted vertebra may have a recent fracture, there is the
potential of PMMA leakage. The PMMA cement contains radiopaque
materials so that when injected under live fluoroscopy, cement
localization and leakage can be observed. The visualization of PMMA
injection and extravasation are critical to the technique--and the
physician terminates PMMA injection when leakage is evident. The
cement is injected using syringes to allow the physician manual
control of injection pressure.
[0009] Kyphoplasty is a modification of percutaneous
vertebroplasty. Kyphoplasty involves a preliminary step consisting
of the percutaneous placement of an inflatable balloon tamp in the
vertebral body. Inflation of the balloon creates a cavity in the
bone prior to cement injection. The proponents of percutaneous
kyphoplasty have suggested that high pressure balloon-tamp
inflation can at least partially restore vertebral body height. In
kyphoplasty, some physicians state that PMMA can be injected at a
lower pressure into the collapsed vertebra since a cavity exists,
when compared to conventional vertebroplasty.
[0010] The principal indications for any form of vertebroplasty are
osteoporotic vertebral collapse with debilitating pain. Radiography
and computed tomography must be performed in the days preceding
treatment to determine the extent of vertebral collapse, the
presence of epidural or foraminal stenosis caused by bone fragment
retropulsion, the presence of cortical destruction or fracture and
the visibility and degree of involvement of the pedicles.
[0011] Leakage of PMMA during vertebroplasty can result in very
serious complications including compression of adjacent structures
that necessitate emergency decompressive surgery. See "Anatomical
and Pathological Considerations in Percutaneous Vertebroplasty and
Kyphoplasty: A Reappraisal of the Vertebral Venous System", Groen,
R. et al, Spine Vol. 29, No. 13, pp 1465-1471 2004. Leakage or
extravasation of PMMA is a critical issue and can be divided into
paravertebral leakage, venous infiltration, epidural leakage and
intradiscal leakage. The exothermic reaction of PMMA carries
potential catastrophic consequences if thermal damage were to
extend to the dural sac, cord, and nerve roots. Surgical evacuation
of leaked cement in the spinal canal has been reported. It has been
found that leakage of PMMA is related to various clinical factors
such as the vertebral compression pattern, and the extent of the
cortical fracture, bone mineral density, the interval from injury
to operation, the amount of PMMA injected and the location of the
injector tip. In one recent study, close to 50% of vertebroplasty
cases resulted in leakage of PMMA from the vertebral bodies. See
Hyun-Woo Do et al, "The Analysis of Polymethylmethacrylate Leakage
after Vertebroplasty for Vertebral Body Compression Fractures",
Jour. of Korean Neurosurg. Soc. Vol. 35, No. 5 (5/2004) pp. 478-82,
(http://www jkns.or.kr/htm/abstract.asp?no=0042004086).
[0012] Another recent study was directed to the incidence of new
VCFs adjacent to the vertebral bodies that were initially treated.
Vertebroplasty patients often return with new pain caused by a new
vertebral body fracture. Leakage of cement into an adjacent disc
space during vertebroplasty increases the risk of a new fracture of
adjacent vertebral bodies. See Am. J. Neuroradiol. 2004 February;
25(2):175-80. The study found that 58% of vertebral bodies adjacent
to a disc with cement leakage fractured during the follow-up period
compared with 12% of vertebral bodies adjacent to a disc without
cement leakage.
[0013] Another life-threatening complication of vertebroplasty is
pulmonary embolism. See Bernhard, J. et al, "Asymptomatic diffuse
pulmonary embolism caused by acrylic cement: an unusual
complication of percutaneous vertebroplasty", Ann. Rheum. Dis.
2003;62:85-86. The vapors from PMMA preparation and injection also
are cause for concern. See Kirby, B, et al., "Acute bronchospasm
due to exposure to polymethylmethacrylate vapors during
percutaneous vertebroplasty", Am. J. Roentgenol. 2003;
180:543-544.
[0014] In both higher pressure cement injection (vertebroplasty)
and balloon-tamped cementing procedures (kyphoplasty), the methods
do not provide for well controlled augmentation of vertebral body
height. The direct injection of bone cement simply follows the path
of least resistance within the fractured bone. The expansion of a
balloon applies also compacting forces along lines of least
resistance in the collapsed cancellous bone. Thus, the reduction of
a vertebral compression fracture is not optimized or controlled in
high pressure balloons as forces of balloon expansion occur in
multiple directions.
[0015] In a kyphoplasty procedure, the physician often uses very
high pressures (e.g., up to 200 or 300 psi) to inflate the balloon
which crushes and compacts cancellous bone. Expansion of the
balloon under high pressures close to cortical bone can fracture
the cortical bone, typically the endplates, which can cause
regional damage to the cortical bone with the risk of cortical bone
necrosis. Such cortical bone damage is highly undesirable as the
endplate and adjacent structures provide nutrients for the
disc.
[0016] Kyphoplasty also is problematic in that balloon inflation
expansion does not slowly expand to displace and compact cancellous
bone. Instead, the balloon in restrained in a substantially
compacted shape until the inflation forces overcome the resistance
of the ceramic-like cancellous bone at which time the balloon
explosively expands. Such explosive expansion of the balloon can
cause fat in the bone marrow as well as blood to be displaced into
the venous system--wherein the fat can result in dangerous
emboli.
[0017] There is a general need to provide bone cements and methods
for use in treatment of vertebral compression fractures that
provide a greater degree of control over introduction of cement and
that provide better outcomes. The present invention meets this need
and provides several other advantages in a novel and nonobvious
manner.
SUMMARY OF THE INVENTION
[0018] Certain embodiments disclosed herein provide vertebroplasty
systems for infill of abnormal bone without the possibility of
extravasation. One embodiment comprises an implant body that is
elongated and substantially strong to allow the body to be driven
axially or helically through an introducer into bone. At the distal
end of the introducer, the elongated implant yields to a thermal
mechanical energy to transform into a non-elongated configuration
for filling a controlled geometry in the bone.
[0019] In accordance with one embodiment, a system for treating
bone is provided. The system comprises an elongated introducer
configured for insertion in a bone, the introducer defining a
passage extending therethrough along an axis of the introducer, and
an elongated implant body configured for insertion through the
passage into the bone, the elongated implant body having a
substantially unyielding configuration. The system also comprises
an energy source coupled to the elongated introducer, the energy
source configured to transform at least a portion of the elongated
implant into a yielding configuration to infill the bone.
[0020] In accordance with another embodiment, a system for treating
a vertebra is provided, comprising an elongated introducer
configured for insertion in a vertebral body, the introducer
defining a passage extending therethrough along an axis of the
introducer. The system also comprises a substantially rigid implant
configured for insertion through the passage into the vertebral
body, the implant comprising a plurality of implant elements
coupled with each other via a junction, the junction transformable
between a substantially unyielding configuration to a substantially
yielding configuration. The system further comprises an energy
source coupled to the elongated introducer, the energy source
configured to separate at least one implant element from the
implant at said junction, the separated implant element advanced
into the vertebral body to infill the vertebral body.
[0021] In accordance with still another embodiment, a system for
the infill of the interior of a bone is provided. The system
comprises an elongated introducer configured for introduction into
a bone, the introducer defining a passage extending therethrough
along an axis of the introducer. The system also comprises a
plurality of implants dimensioned for advancement along the
introducer, each adjacent pair of the plurality of implants coupled
to each other via a junction, each implant having a first helical
feature for cooperating with a second helical feature on the
introducer to helically advance the implants through the passage
and into the bone.
[0022] In accordance with yet another embodiment, a system for
treating a bone is provided. The system comprises an elongated
introducer configured for insertion into a bone, the introducer
defining a passage extending therethrough along an axis of the
introducer. The system also comprises an elongated implant body
configured for insertion into the bone along said introducer, the
elongated implant body having a substantially unyielding
configuration, a surface of the implant body configured to engage
with a surface of the introducer for advancement of the implant
body along the introducer. The system further comprises means for
transforming at least a portion of the elongated implant from a
substantially unyielding configuration to a yielding configuration
to infill the bone.
[0023] In accordance with another embodiment, an implant configured
for insertion into a bone is provided. The implant comprises an
elongated body sized for introduction along an introducer into a
bone, at least a portion of the elongated body being transformable
from a substantially unyielding configuration to a yielding
configuration configured for infilling the bone.
[0024] In accordance with still another embodiment, an implant
configured for insertion into a bone is provided, comprising an
elongated body having at least one helical feature and sized for
introduction into a bone, at least a portion of the elongated body
being severable from the elongated portion for infilling the
bone.
[0025] In accordance with one embodiment, a method for treating a
vertebral body is provided. The method comprises advancing an
elongated implant body through an introducer and into an interior
of a vertebral body, the elongated implant body having a first
configuration that is substantially unyielding along a longitudinal
axis of the body. The method also comprises transforming the
implant body to a second configuration that yields its first
configuration proximate to a working end of the introducer for
infilling a region of the vertebral body.
[0026] In accordance with another embodiment, a method for treating
a bone is provided. The method comprises inserting an introducer
into a bone, helically driving an elongated implant body relative
to the introducer, the implant body having a first elongated
configuration, and transforming at least a portion of the implant
body into a second non-elongated configuration for infilling a
region of the bone.
[0027] In accordance with still another embodiment, a method for
treating a vertebra is provided. The method comprises positioning a
distal end of an introducer in an interior of a vertebra, and
helically driving at least one implant body comprising a helical
feature through the introducer to thereby deploy the implant body
in the interior of the vertebra, the helical feature engaging a
cooperating feature on the introducer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to better understand the invention and to see how
it may be carried out in practice, some preferred embodiments are
next described, by way of non-limiting examples only, with
reference to the accompanying drawings, in which like reference
characters denote corresponding features consistently throughout
similar embodiments in the attached drawings.
[0029] FIG. 1A is a schematic perspective view of spine segment
showing an introducer in a pedicular access.
[0030] FIG. 1B is a schematic view of the spine segment of FIG. 1A
from a different angle.
[0031] FIG. 2A is a perspective schematic view of a bone implant
and introducer in accordance with one embodiment.
[0032] FIG. 2B is a perspective schematic view of a bone implant
and introducer in accordance with another embodiment.
[0033] FIG. 2C is a perspective schematic view of a bone implant
and introducer in accordance with yet another embodiment.
[0034] FIG. 3 is a schematic view of the implant and introducer of
FIG. 2 in a method using thermal energy to alter a property of a
polymer implant, in accordance with one embodiment.
[0035] FIG. 4 is a plan schematic view of another implant body with
helical features for cooperating with a threaded introducer, in
accordance with another embodiment.
[0036] FIG. 5 is a schematic view of the implant body and
introducer of FIG. 4 in a method using Rf energy to alter a
property of a polymer implant being used in a vertebral body
treatment, in accordance with one embodiment.
[0037] FIG. 6 is a plan schematic view of another implant body with
helical features for cooperating with a threaded introducer similar
to that of FIG. 4 with spaced apart fracturable portions.
[0038] FIG. 7 is a sectional schematic view of another implant body
with helical features in the interior of the body and polygonal
features on the exterior surface of the body with spaced apart
fracturable portions.
[0039] FIG. 8 is a sectional schematic view of a portion of another
implant body with helical features and regions that are adapted to
be cut at a distal end of an introducer.
[0040] FIG. 9 is a plan schematic view of another implant system
comprising a plurality of elements with helical features for
cooperating with a threaded introducer.
[0041] FIG. 10 is a schematic view of the implant elements and
introducer of FIG. 9 in a method of infilling a vertebral body.
[0042] FIG. 11 is a schematic view of another form of implant
elements with helical features in an interior bore for use in
infilling a vertebral body.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] Referring to FIGS. 1A and 1B, one embodiment of bone fill
introducer or injector system 100A is shown that is configured for
treatment of an abnormal vertebra 102 such as in the case of a
vertebral compression fracture. Introducer system 100A as in FIGS.
2A-C includes introducer sleeve 105 with passageway 108 therein
that is configured for the introduction of an elongated implant
body 110A therethrough to a targeted site 112 in a vertebra (see
FIGS. 1A-1B). As can be seen in FIG. 2, the elongated implant body
110A has a first configuration that is substantially unyielding
along a longitudinal axis 115 of the body. The term "unyielding" as
used herein means that the implant body is substantially rigid,
inflexible and sufficiently strong to allow the implant to be
axially pushed or driven through passageway 108 in the introducer
sleeve 105. The implant body is preferably of a polymeric material,
a ceramic material, a glass material or a combination thereof that
allows transformation of the implant to a "yielding" material at
the working end 120 of the introducer 105 for filling the targeted
site. The term "yielding" is used to describe that implant as
having a softened, melted, fractured, cut, partially sacrificed or
other "yielded" or "yielding" configuration that will be described
in more detail below.
[0044] One embodiment of a method for treating a vertebra includes
providing the implant body described above, advancing the implant
body 110A through the introducer passageway 108 or channel to exit
the open end or outlet 122 thereof into an interior of a vertebra,
and transforming the implant body to a second configuration 110A'
(FIG. 3) that yields its first configuration proximate to working
end 120 of sleeve 105 to thereby allow infilling a site 112 in the
vertebra wherein the implant forms a more or less compacted form
and geometry (see FIG. 3), rather than an elongated geometry as
when the implant is inserted into the proximal or handle end 130 of
sleeve 105. As can be seen in FIGS. 2A-C, the introducer has a
side-directed outlet 122 in the working end but the outlet also can
be distally oriented as the end of a needle.
[0045] In one embodiment, still referring to FIGS. 2A-C, the means
for transforming the implant from the substantially rigid or
unyielding configuration of FIGS. 2A-C to the softened, yielding
configuration of FIG. 3 comprises a thermal energy deliver means or
emitter in the form of resistively heated coil emitter or a
resistively heated positive temperature coefficient of resistance
(PTCR) emitter 140A, 140B or 140C in bore 108 in the working end
120. In FIG. 2A, it can be seen that handle 130 coupled to
introducer sleeve 105 includes an electrical connector 142 for
coupling electrical source 150A to the connector by means of
electrical cable 152. The system further includes a controller 155
for controlling electrical energy delivery to the coil or PTCR
emitter 140A. In one embodiment, the working end 120 carries a
thermocouple 156 proximate to the coil or PTCR emitter 140A or
electrode that is operatively coupled to the controller for
modulating energy delivery to the emitter to thereby control
heating of the implant body 110A. In operation, (i) the implant
110A is introduced through the sleeve 105, (ii) the emitter 140A is
contemporaneously actuated in distal portion of the introducer
bore, and (iii) the implant body is pushed into cancellous bone 158
wherein the softened implant body 110A' becomes a convoluted mass
and thus applies height restoring forces on the VCF. As can be seen
in FIG. 2A, the drive mechanism indicated at 160 can be any means
of applying force such as a human hand, a mechanical assist drive
system such as a gear which cooperates with surface features on the
implant body, a hydraulic assist drive system, a helical drive
system (as described below) or the like.
[0046] The implant body 110A can be any form of biocompatible
polymer such as a PMMA that is softenable or meltable by heating.
The implant system can further include the introduction of a
hardenable bone cement together with implant body 110A by another
inflow channel in the introducer. Alternatively, the implant body
can be configured with surfaces that fuse together upon heating to
provide higher strength in the convoluted form (FIG. 3).
[0047] FIGS. 4 and 5 illustrate another system embodiment 110B with
the implant body 110B having helical surface features indicated as
threads 165 that cooperate with threaded features 166 in at least a
portion of bore 108 in sleeve 105. A motor drive or hand drive can
rotate an elongated polygonal shaft that is configured to mate with
polygonal (hex) bore 170 in the implant body for driving the
implant. In the embodiment of FIGS. 4 and 5, the thermal energy
emitter comprises opposing polarity electrodes 175A and 175B that
carry Rf energy to an electrically conductive implant body 110B.
For example, the polymeric implant can be conductively doped with
carbon, a metal or the like in the form of particles, filaments or
the like. In use, referring to FIG. 5, the system can be used with
high energy densities to cause a fuse-like sacrificial melt of
portions of the implant body at various locations along the
implant. Alternatively, the system can continuously heat and soften
the implant body 110B or a combination of softening, melting of
cutting the implant body is possible. The system can be use to melt
a thermoplastic implant wherein the material retains a very high
viscosity, and even a low temperature in comparison to a
conventional bone cement, which prevents extravasation. Bone cement
130 can be introduced into the bone as well (FIG. 5).
[0048] The embodiments of FIGS. 2A and 5 above described implant
bodies 110A and 110B that are transformed to a yielding
configuration via resistive heating or Rf ohmic heating of the
implant. However, in another system 100A' an energy source 150B for
applying thermal energy to heat the implant and optionally bone
tissue can include at least one of an Rf source, a resistive heat
source, a light energy source, a microwave source, an ultrasound
source, a magnetic source, as shown schematically in FIG. 2B. The
energy source 150B can apply energy to the implant via an energy
emitter 140B. The material of the implant can carry any
biocompatible material that is responsive to a particular energy
source such as a chromophore, a ferromagnetic material or the like.
Thermal energy application to the implant can transform the implant
body into a compliant configuration, melt at least portions of the
implant body, sever or cut the implant body, soften and make
flexible at least portions of the implant body, or sacrifice
portions of an inflexible implant. The thermal energy emitter is
disposed at any suitable location in the introducer sleeve 105.
[0049] In another embodiment, an implant delivery system 100A'' can
include a cryogenic source 150C capable of fragmenting or
fracturing at least portions of the implant body. For example a
Freon spray can be directed at the implant 110A at a location 140C
to weaken, freeze and fracture the distal end of an implant wherein
further driving of the implant through the introducer will cause
the injection of fragments of the implant body.
[0050] In summary, the method of transforming the implant body from
unyielding to yielding can utilize at least one of thermal energy
application, mechanical energy application and cryogenic cooling to
the implant body.
[0051] FIG. 6 shows another embodiment of implant body 110C that
again has a helical configuration for driving through an introducer
sleeve 105 similar to FIGS. 4 and 5. Again, the implant can be
driven by a hex rod extending through a bore 178 in the implant. In
this embodiment, the implant has spaced apart sacrificial or
softenable portions 180 that are configured to fracture, melt,
dissolve, or fragment upon thermal energy application, mechanical
energy application, chemical application and/or cryogenic cooling
to a targeted portion 180 of the implant body. In one embodiment,
mechanical force can be applied to implant 110C at the distal end
125 of an introducer sleeve by a bend in the bore 108 of the
introducer sleeve 105 as in the side outlet 122 of FIG. 2A.
[0052] FIG. 7 shows a similar embodiment of implant body 110D that
differs in that the helical features 185 are within an interior
bore of the implant body that cooperates with threads 188 on shaft
190. The shaft has bore 192 therein that can be used for bone
cement delivery. The implant body 110D in this case is driven by an
outer sleeve 195 having a polygonal surface that cooperates with a
similar surface of the implant body. In this embodiment, the
sacrificial or softenable portions 180 are spaced apart and adapted
to fracture mechanically by a change in thread pitch in region
196.
[0053] FIG. 8 shows another embodiment of implant body 110E with
helical features 205 that are again adapted to cooperate with
threads in an interior bore 108 of a sleeve 105 as in FIG. 4. In
this embodiment, the sleeve 105 (phantom view) carries blades 210
that are adapted to cut the implant body into flexible strips 212a
and 212b for packing into a bone. The implant is again driven by a
polygonal rod that engages a central bore in the implant body as
described above. The implant body can have a weakened plane about
where it is to be cut mechanically.
[0054] In any of the embodiments of FIGS. 6, 7 and 8, the implant
body can be any biocompatible metal with the fracturable portion
being any suitable material such as a polymer.
[0055] In any of the embodiments of FIGS. 2A-8, the implant body
can be include or comprise a radiopaque composition.
[0056] FIGS. 9 and 10 illustrate another embodiment of the
invention wherein a plurality of implant elements 220 have helical
features 222 that again are adapted to cooperate with threads in an
interior bore 108 of a sleeve 105 (cf. FIG. 4). In this embodiment,
the implant elements 220 have cooperating key features 222a and
222b to allow cooperative rotation of the assembly for advancement
through the sleeve 105. FIG. 10 illustrates a schematic view of a
plurality of the elements in a targeted site 112. In another
similar embodiment, the elements can be short metal helically
formed wires that look a bit like springs that co-operate with a
thread feature in at least a distal portion of an introducer
sleeve. Such metal wire forms can have a wire feature or molded
insert that cooperates with a polygonal driver for helically
driving the elements.
[0057] FIG. 11 illustrates another embodiment of the invention
wherein a plurality of implant elements 228 have interior helical
features that are adapted to cooperate with threads 230 on shaft
232 and the elements 228 are driven by a polygonal outer sleeve
240.
[0058] The above description is intended to be illustrative and not
exhaustive. Particular characteristics, features, dimensions and
the like that are presented in dependent claims can be combined and
fall within the scope of the invention. The invention also
encompasses embodiments as if dependent claims were alternatively
written in a multiple dependent claim format with reference to
other independent claims. Specific characteristics and features of
the invention and its method are described in relation to some
figures and not in others, and this is for convenience only. While
the principles of the invention have been made clear in the above
descriptions and combinations, it will be obvious to those skilled
in the art that modifications may be utilized in the practice of
the invention, and otherwise, which are particularly adapted to
specific environments and operative requirements without departing
from the principles of the invention. The appended claims are
intended to cover and embrace any and all such modifications, with
the limits only of the true purview, spirit and scope of the
invention.
[0059] Other features and methods that may be incorporated with the
above embodiments may be found in U.S. patent application Ser. No.
11/165,652, filed Jun. 24, 2005; U.S. patent application Ser. No.
11/165,651, filed Jun. 24, 2005, U.S. patent application Ser. No.
11/208,448, filed Aug. 20, 2005; U.S. patent application Ser. No.
11/469,764, filed Sep. 1, 2006; and U.S. application Ser. No.
11/209,035, filed Aug. 22, 2005; and U.S. application Ser. No.
11/196,045, filed Aug. 2, 2005, the entirety of each of which is
hereby incorporated by reference.
[0060] Of course, the foregoing description is that of certain
features, aspects and advantages of the present invention, to which
various changes and modifications can be made without departing
from the spirit and scope of the present invention. Moreover, the
bone treatment systems and methods need not feature all of the
objects, advantages, features and aspects discussed above. Thus,
for example, those skill in the art will recognize that the
invention can be embodied or carried out in a manner that achieves
or optimizes one advantage or a group of advantages as taught
herein without necessarily achieving other objects or advantages as
may be taught or suggested herein. In addition, while a number of
variations of the invention have been shown and described in
detail, other modifications and methods of use, which are within
the scope of this invention, will be readily apparent to those of
skill in the art based upon this disclosure. It is contemplated
that various combinations or subcombinations of these specific
features and aspects of embodiments may be made and still fall
within the scope of the invention. Accordingly, it should be
understood that various features and aspects of the disclosed
embodiments can be combined with or substituted for one another in
order to form varying modes of the discussed bone treatment systems
and methods.
* * * * *
References